1. Field of the Invention
This invention relates to therapeutic nasal inhalation and, more particularly, to a method for intercepting air exhaled during a normal breathing cycle so that controlled quantities of the exhaled air can be inhaled by an individual.
2. Background Art
It is well known that conditions such as anxiety, chronic stress, asthma, and the like, may lead to over-breathing or hyperventilation. Contrary to intuition, hyperventilation, which can occur with unusually deep or rapid breathing, can create an oxygen deficiency in the blood. The mechanism is as follows. As inhaled oxygen levels exceed the body's metabolic demands, blood CO2 levels decrease and blood carbonic acid levels lower, creating a corresponding increase in blood pH levels making the blood more alkaline. In alkaline blood, oxygen is tightly bound to the hemoglobin impeding the oxygenation of the body's tissues, leading to symptoms such as dizziness and feelings of detachment or numbness and tingling in the toes or fingers, depending on whether the lowered oxygen levels are in the brain or at the extremities.
It is generally accepted that increasing blood CO2 levels is a factor in causing the widening of blood vessels (vasodilation), which leads to a lowering of blood pressure. Many consider that work/life-related stress can trigger a temporary increase in blood pressure. As described by Herbert Benson in “The Relaxation Response,” a means of lowering blood pressure can be associated with the body being in a relaxed state.
One way of increasing CO2 levels is by re-breathing CO2 rich exhaled air collected in a paper bag, commonly known to reverse the effects of hyperventilation such as occurs during an anxiety attack.
In the early 1960's, a breathing method was developed that similarly abates hyperventilation by effectively decreasing the amount of oxygen inhaled. Known as the Buteyko breathing technique (BBT), it is based on a theory that “hidden hyperventilation” is a characteristic of asthmatic breathing. While most people have experienced hyperventilation to some degree, studies indicate asthmatics may breathe 2.5 times more air per minute than healthy adults. The BBT teaches asthmatics to breathe less by reducing the depth and frequency of inhalations, thus reducing the amount of inhaled oxygen. The result is that the drop in CO2 levels is reversed and the symptoms of blood alkalinity, dizziness, detachment, etc., that typically occur when one is having difficulty breathing, are reduced.
The BBT has been shown to successfully and safely reduce asthma/hyperventilation symptoms and the need for medication. Though this method was developed nearly 50 years ago, its effectiveness was formally recognized when the British Guideline on the Management of Asthma in 2008 deemed the BBT appropriate for health professionals in the United Kingdom to recommend to their patients. However, to achieve the results reported requires daily exercises over a period of weeks or months.
Apparatus for re-breathing CO2, as described by Exler (U.S. Pat. No. 3,513,843), and for administering CO2, as described by Hicks (U.S. Pat. No. 2,007,330), both use a vessel to collect exhaled air and a mask covering the nose and mouth for re-breathing.
Similarly, the breathing exercise in Navara (U.S. Pat. No. 3,949,984) and the re-breathing apparatus for use with hyperventilating patients, described by Hardwick (U.S. Pat. No. 4,192,301), require an inflatable bag to collect exhaled air, which is re-breathed through a mouth and nose/mouth mask, respectively. Furthermore, Hardwick connects the nose/mouth mask to a proportioning valve to adjust the proportion of re-breathed to fresh air inhaled.
Sorensen (U.S. Pat. No. 4,275,722) teaches a method of mixing exhaled air with fresh air to increase the CO2 content of the air inhaled. However, this is done by using inhalation and exhalation chambers while breathing through the mouth. Other breathing apparatus, Downey (U.S. Pat. No. 6,880,557), Hougen (U.S. Pat. Nos. 5,899,832; 5,910,071; and 6,083,141), and Duncan et al. (U.S. Pat. Nos. 4,508,116; and 4,628,926) have some form of vessel into which exhaled air is collected.
Hepburn (U.S. Pat. No. 5,154,167) describes a lung and chest exercise and developer “that arranges for some of the air expired from the lungs on an outbreath to be collected and then to be breathed back into the lungs on the next inbreath, together with some fresh air.” This device has a mouthpiece with a collector bag consisting of a top and bottom portion and a structure for restricting the amount of fresh air. A nosepiece can be added to restrict airflow through the nose. This apparatus requires a collection bag and the mixing of exhaled air with fresh air by restricting airflow in some manner.